Dizygotic, commonly known as fraternal twins, occurs when two separate eggs are fertilized by two different sperm cells during the same menstrual cycle. This results in two genetically unique siblings who share about 50% of their DNA, similar to regular siblings born at different times. Dizygotic twins can be of the same sex or different sexes, and they may or may not look alike. Factors influencing the likelihood of having dizygotic twins include maternal age, family history, and certain fertility treatments. Unlike monozygotic twins, who originate from a single fertilized egg, dizygotic twins develop independently.